Investigation of wicking phenomenon and tensile properties in three-layer composite nanofibrous PA/PLLA yarn

One critical property of a nanofibrous structure is the wicking behavior in contact with liquids. This work's purpose is fabrication and investigation of tensile and wicking properties of a newly designed three-layer nanofibrous yarn consisting of polyamide 6/poly(L-lactic acid) (PA/PLLA) with a similar idea to Bobtex spun yarn structure in which adhesion between core (PA) and sheath (PLLA) is provided with a thin layer of polymeric thin film. The tensile strength and strain decreased 32 and 46%, respectively, in a three-layer yarn compared with two-layer, that is, yarn without the adhesion film. In addition, the ultimate strength of the three-layer yarn was higher than a PLLA yarn. The vertical wicking test for three-layer nanofibrous yarn reveals that at short times, capillary rise kinetics follow the Lucas–Washburn law while increasing the take-up velocity of the take-up roller in yarn fabrication leads to increasing the maximum height of water in yarn.